Multisensory Integration and Human Postural Control

描述（由申请人提供）：本研究的长期目标是了解神经系统如何结合来自多个感官的信息来控制多节段人体直立姿势。不平衡是导致跌倒相关伤害的主要原因，到2020年，医疗保健系统的成本预计将超过320亿美元。目前改善平衡和降低跌倒风险的干预措施缺乏理论框架，因为它们影响姿势控制过程的机制尚未得到很好的理解。在平衡赤字背后的控制过程被理解之前，康复计划将继续以昂贵且耗时的非特定方式进行干预。该建议强调了一种实验策略，旨在以比现有方法更确定的方式探索患者群体中潜在的姿势控制回路。十个实验将探讨三个具体目标。1 .确定多关节姿势控制的开环频率响应函数。2。探讨多式联运重加权的动态。3。探讨双侧前庭功能丧失患者多关节控制策略的适应性。我们建议在之前的研究成果的基础上，通过操纵两种感官输入的不同组合来关注多感官重加权的特性。此外，我们将扩展先前为单关节姿势控制开发的系统识别技术。多个同时的机械和感官扰动将确定肌肉活动如何转化为对身体部分位置（植物）的控制，以及身体部分位置如何转化为新的肌肉活动（反馈）。这种识别将在多关节体的背景下实现，其相对构型必须纳入身体动力学的估计。最后，将健康和双侧前庭功能丧失的个体与这些识别技术进行比较，以确定前庭功能丧失如何破坏植物和反馈控制回路。有了这些知识，康复工作就可以着重于控制回路内某一特定过程的方法，以优化康复，从而实现更有效、更有针对性的护理，并降低医疗保健成本。本研究的长期目标是了解神经系统如何融合来自多个感觉系统的信息来控制多节段人类直立姿势。对社会的意义在于，涉及两足平衡的神经/生物力学系统容易受到损伤和功能障碍，导致平衡控制能力差，治疗方案有限。不平衡是跌倒的主要原因，在老年人中与功能下降和虚弱密切相关。社会的代价是巨大的。1994年，65岁以上人群跌倒伤害的总成本为204亿美元，预计到2020年将超过320亿美元，这导致国会制定立法，扩大与跌倒相关的研究和减少跌倒风险的计划（众议院决议3695,2002）。

DESCRIPTION (provided by applicant): The long-term goal of this research is to understand how the nervous system combines information from multiple senses for the control of multisegment human upright stance. Imbalance is a major cause of fall- related injuries, whose cost to the health-care system is expected to exceed $32B by 2020. Current interventions to improve balance and reduce the risk for falls lack a theoretical framework because the mechanisms by which they affect postural control processes are not well understood. Until the control processes underlying a balance deficit are understood, rehabilitative programs will continue to intervene in costly and time-consuming non-specific ways. This proposal emphasizes an experimental strategy designed to probe the underlying postural control loop in patient populations with far more certainty than present methods. Ten experiments will investigate three specific aims. I. To identify open-loop frequency response functions characterizing multijoint postural control. II. To investigate the dynamics of intermodality reweighting. III. To investigate the adaptability of the multijoint control strategy in bilateral vestibular loss (BVL) patients. We propose to build on the findings from previous grant cycles focusing on the properties of multisensory reweighting by manipulating different combinations of two sensory inputs. In addition, we will expand a system identification technique previously developed for single-joint postural control. Multiple, simultaneous, mechanical and sensory perturbations will identify how muscular activity translates into control of body segment positions (the plant) and how, in turn, body segment positions translate into new muscular activity (feedback). This identification will be achieved within the context of the multi-joint body, whose relative configuration must be incorporated into the estimate of body dynamics. Finally, healthy and bilateral vestibular loss individuals will be compared with these identification techniques to determine how loss of vestibular function disrupts the plant and feedback control loops. With such knowledge, rehabilitative efforts may then emphasize methods that focus on a particular process within the control loop to optimize rehabilitation, leading to more effective, targeted care and reduction of health care costs. PUBLIC HEALTH RELEVANCE The long-term goal of this research is to understand how the nervous system fuses information from multiple sensory systems for the control of multisegment human upright stance. The significance to society is that the neural/biomechanical systems involved in bipedal balance are subject to injury and dysfunction, leading to poor balance control with limited treatment options. Imbalance is a major cause of falls and in older adults is strongly associated with functional decline and frailty. The cost to society is enormous. Total costs of fall injuries for people 65+ in 1994 were $20.4 B and are expected to exceed $32B by 2020, leading Congress to institute legislation expanding fall-related research and fall-risk reduction programs (House Resolution 3695, 2002).